/** @license
 * Copyright 2016 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

goog.provide('shaka.polyfill.PatchedMediaKeysMs');

goog.require('goog.asserts');
goog.require('shaka.log');
goog.require('shaka.media.DrmEngine');
goog.require('shaka.polyfill');
goog.require('shaka.util.BufferUtils');
goog.require('shaka.util.EventManager');
goog.require('shaka.util.FakeEvent');
goog.require('shaka.util.FakeEventTarget');
goog.require('shaka.util.Pssh');
goog.require('shaka.util.PublicPromise');


/**
 * @summary A polyfill to implement
 * {@link https://bit.ly/EmeMar15 EME draft 12 March 2015}
 * on top of ms-prefixed
 * {@link https://www.w3.org/TR/2014/WD-encrypted-media-20140218/ EME v20140218}
 */
shaka.polyfill.PatchedMediaKeysMs = class {
  /**
   * Installs the polyfill if needed.
   */
  static install() {
    if (!window.HTMLVideoElement || !window.MSMediaKeys ||
        (navigator.requestMediaKeySystemAccess &&
         // eslint-disable-next-line no-restricted-syntax
         MediaKeySystemAccess.prototype.getConfiguration)) {
      return;
    }
    shaka.log.info('Using ms-prefixed EME v20140218');

    // Alias
    const PatchedMediaKeysMs = shaka.polyfill.PatchedMediaKeysMs;

    // Delete mediaKeys to work around strict mode compatibility issues.
    // eslint-disable-next-line no-restricted-syntax
    delete HTMLMediaElement.prototype['mediaKeys'];
    // Work around read-only declaration for mediaKeys by using a string.
    // eslint-disable-next-line no-restricted-syntax
    HTMLMediaElement.prototype['mediaKeys'] = null;

    // Install patches
    window.MediaKeys = PatchedMediaKeysMs.MediaKeys;
    window.MediaKeySystemAccess = PatchedMediaKeysMs.MediaKeySystemAccess;
    navigator.requestMediaKeySystemAccess =
        PatchedMediaKeysMs.requestMediaKeySystemAccess;
    // eslint-disable-next-line no-restricted-syntax
    HTMLMediaElement.prototype.setMediaKeys =
        PatchedMediaKeysMs.MediaKeySystemAccess.setMediaKeys;
  }

  /**
   * An implementation of navigator.requestMediaKeySystemAccess.
   * Retrieves a MediaKeySystemAccess object.
   *
   * @this {!Navigator}
   * @param {string} keySystem
   * @param {!Array.<!MediaKeySystemConfiguration>} supportedConfigurations
   * @return {!Promise.<!MediaKeySystemAccess>}
   */
  static requestMediaKeySystemAccess(keySystem, supportedConfigurations) {
    shaka.log.debug('PatchedMediaKeysMs.requestMediaKeySystemAccess');
    goog.asserts.assert(this == navigator,
        'bad "this" for requestMediaKeySystemAccess');

    // Alias.
    const PatchedMediaKeysMs = shaka.polyfill.PatchedMediaKeysMs;
    try {
      const access = new PatchedMediaKeysMs.MediaKeySystemAccess(
          keySystem, supportedConfigurations);
      return Promise.resolve(/** @type {!MediaKeySystemAccess} */ (access));
    } catch (exception) {
      return Promise.reject(exception);
    }
  }

  /**
   * Handler for the native media elements msNeedKey event.
   *
   * @this {!HTMLMediaElement}
   * @param {!MediaKeyEvent} event
   * @private
   */
  static onMsNeedKey_(event) {
    shaka.log.debug('PatchedMediaKeysMs.onMsNeedKey_', event);
    if (!event.initData) {
      return;
    }

    // NOTE: Because "this" is a real EventTarget, on IE, the event we dispatch
    // here must also be a real Event.
    const event2 =
    /** @type {!CustomEvent} */ (document.createEvent('CustomEvent'));
    event2.initCustomEvent('encrypted', false, false, null);
    event2.initDataType = 'cenc';
    event2.initData = shaka.util.Pssh.normaliseInitData(event.initData);

    this.dispatchEvent(event2);
  }
};


/**
 * An implementation of MediaKeySystemAccess.
 *
 * @implements {MediaKeySystemAccess}
 */
shaka.polyfill.PatchedMediaKeysMs.MediaKeySystemAccess = class {
  /**
   * @param {string} keySystem
   * @param {!Array.<!MediaKeySystemConfiguration>} supportedConfigurations
   */
  constructor(keySystem, supportedConfigurations) {
    shaka.log.debug('PatchedMediaKeysMs.MediaKeySystemAccess');

    /** @type {string} */
    this.keySystem = keySystem;

    /** @private {!MediaKeySystemConfiguration} */
    this.configuration_;

    const allowPersistentState = false;

    let success = false;
    for (const cfg of supportedConfigurations) {
      // Create a new config object and start adding in the pieces which we
      // find support for.  We will return this from getConfiguration() if
      // asked.
      /** @type {!MediaKeySystemConfiguration} */
      const newCfg = {
        'audioCapabilities': [],
        'videoCapabilities': [],
        // It is technically against spec to return these as optional, but we
        // don't truly know their values from the prefixed API:
        'persistentState': 'optional',
        'distinctiveIdentifier': 'optional',
        // Pretend the requested init data types are supported, since we don't
        // really know that either:
        'initDataTypes': cfg.initDataTypes,
        'sessionTypes': ['temporary'],
        'label': cfg.label,
      };

      // PatchedMediaKeysMs tests for key system availability through
      // MSMediaKeys.isTypeSupported
      let ranAnyTests = false;
      if (cfg.audioCapabilities) {
        for (const cap of cfg.audioCapabilities) {
          if (cap.contentType) {
            ranAnyTests = true;
            const contentType = cap.contentType.split(';')[0];
            if (MSMediaKeys.isTypeSupported(this.keySystem, contentType)) {
              newCfg.audioCapabilities.push(cap);
              success = true;
            }
          }
        }
      }
      if (cfg.videoCapabilities) {
        for (const cap of cfg.videoCapabilities) {
          if (cap.contentType) {
            ranAnyTests = true;
            const contentType = cap.contentType.split(';')[0];
            if (MSMediaKeys.isTypeSupported(this.keySystem, contentType)) {
              newCfg.videoCapabilities.push(cap);
              success = true;
            }
          }
        }
      }

      if (!ranAnyTests) {
        // If no specific types were requested, we check all common types to
        // find out if the key system is present at all.
        success = MSMediaKeys.isTypeSupported(this.keySystem, 'video/mp4');
      }
      if (cfg.persistentState == 'required') {
        if (allowPersistentState) {
          newCfg.persistentState = 'required';
          newCfg.sessionTypes = ['persistent-license'];
        } else {
          success = false;
        }
      }

      if (success) {
        this.configuration_ = newCfg;
        return;
      }
    }  // for each cfg in supportedConfigurations

    // As per the spec, this should be a DOMException, but there is not a
    // public constructor for this.
    const unsupportedKeySystemError = new Error('Unsupported keySystem');
    unsupportedKeySystemError.name = 'NotSupportedError';
    unsupportedKeySystemError.code = DOMException.NOT_SUPPORTED_ERR;
    throw unsupportedKeySystemError;
  }

  /** @override */
  createMediaKeys() {
    shaka.log.debug(
        'PatchedMediaKeysMs.MediaKeySystemAccess.createMediaKeys');

    // Alias
    const PatchedMediaKeysMs = shaka.polyfill.PatchedMediaKeysMs;

    const mediaKeys = new PatchedMediaKeysMs.MediaKeys(this.keySystem);
    return Promise.resolve(/** @type {!MediaKeys} */ (mediaKeys));
  }

  /** @override */
  getConfiguration() {
    shaka.log.debug(
        'PatchedMediaKeysMs.MediaKeySystemAccess.getConfiguration');
    return this.configuration_;
  }

  /**
   * An implementation of HTMLMediaElement.prototype.setMediaKeys.
   * Attaches a MediaKeys object to the media element.
   *
   * @this {!HTMLMediaElement}
   * @param {MediaKeys} mediaKeys
   * @return {!Promise}
   */
  static setMediaKeys(mediaKeys) {
    shaka.log.debug('PatchedMediaKeysMs.setMediaKeys');
    goog.asserts.assert(this instanceof HTMLMediaElement,
        'bad "this" for setMediaKeys');

    // Alias
    const PatchedMediaKeysMs = shaka.polyfill.PatchedMediaKeysMs;

    const newMediaKeys =
    /** @type {shaka.polyfill.PatchedMediaKeysMs.MediaKeys} */ (
        mediaKeys);
    const oldMediaKeys =
    /** @type {shaka.polyfill.PatchedMediaKeysMs.MediaKeys} */ (
        this.mediaKeys);

    if (oldMediaKeys && oldMediaKeys != newMediaKeys) {
      goog.asserts.assert(oldMediaKeys instanceof PatchedMediaKeysMs.MediaKeys,
          'non-polyfill instance of oldMediaKeys');
      // Have the old MediaKeys stop listening to events on the video tag.
      oldMediaKeys.setMedia(null);
    }

    delete this['mediaKeys'];  // in case there is an existing getter
    this['mediaKeys'] = mediaKeys;  // work around read-only declaration

    if (newMediaKeys) {
      goog.asserts.assert(newMediaKeys instanceof PatchedMediaKeysMs.MediaKeys,
          'non-polyfill instance of newMediaKeys');
      return newMediaKeys.setMedia(this);
    }

    return Promise.resolve();
  }
};


/**
 * An implementation of MediaKeys.
 *
 * @implements {MediaKeys}
 */
shaka.polyfill.PatchedMediaKeysMs.MediaKeys = class {
  /** @param {string} keySystem */
  constructor(keySystem) {
    shaka.log.debug('PatchedMediaKeysMs.MediaKeys');

    /** @private {!MSMediaKeys} */
    this.nativeMediaKeys_ = new MSMediaKeys(keySystem);

    /** @private {!shaka.util.EventManager} */
    this.eventManager_ = new shaka.util.EventManager();
  }

  /** @override */
  createSession(sessionType) {
    shaka.log.debug('PatchedMediaKeysMs.MediaKeys.createSession');

    sessionType = sessionType || 'temporary';
    // For now, only the 'temporary' type is supported.
    if (sessionType != 'temporary') {
      throw new TypeError('Session type ' + sessionType +
      ' is unsupported on this platform.');
    }

    // Alias
    const PatchedMediaKeysMs = shaka.polyfill.PatchedMediaKeysMs;

    return new PatchedMediaKeysMs.MediaKeySession(
        this.nativeMediaKeys_, sessionType);
  }

  /** @override */
  setServerCertificate(serverCertificate) {
    shaka.log.debug('PatchedMediaKeysMs.MediaKeys.setServerCertificate');

    // There is no equivalent in PatchedMediaKeysMs, so return failure.
    return Promise.resolve(false);
  }

  /**
   * @param {HTMLMediaElement} media
   * @protected
   * @return {!Promise}
   */
  setMedia(media) {
    // Alias
    const PatchedMediaKeysMs = shaka.polyfill.PatchedMediaKeysMs;

    // Remove any old listeners.
    this.eventManager_.removeAll();

    // It is valid for media to be null; null is used to flag that event
    // handlers need to be cleaned up.
    if (!media) {
      return Promise.resolve();
    }

    // Intercept and translate these prefixed EME events.
    this.eventManager_.listen(media, 'msneedkey',
    /** @type {shaka.util.EventManager.ListenerType} */
        (PatchedMediaKeysMs.onMsNeedKey_));

    const self = this;
    const setMediaKeysDeferred = () => {
      media.msSetMediaKeys(self.nativeMediaKeys_);
      media.removeEventListener('loadedmetadata', setMediaKeysDeferred);
    };

    // Wrap native HTMLMediaElement.msSetMediaKeys with a Promise.
    try {
      // IE11/Edge requires that readyState >=1 before mediaKeys can be set,
      // so check this and wait for loadedmetadata if we are not in the
      // correct state
      if (media.readyState >= 1) {
        media.msSetMediaKeys(this.nativeMediaKeys_);
      } else {
        media.addEventListener('loadedmetadata', setMediaKeysDeferred);
      }

      return Promise.resolve();
    } catch (exception) {
      return Promise.reject(exception);
    }
  }
};


/**
 * An implementation of MediaKeySession.
 *
 * @implements {MediaKeySession}
 */
shaka.polyfill.PatchedMediaKeysMs.MediaKeySession =
    class extends shaka.util.FakeEventTarget {
      /**
       * @param {MSMediaKeys} nativeMediaKeys
       * @param {string} sessionType
       */
      constructor(nativeMediaKeys, sessionType) {
        shaka.log.debug('PatchedMediaKeysMs.MediaKeySession');
        super();

        // The native MediaKeySession, which will be created in
        // generateRequest.
        /** @private {MSMediaKeySession} */
        this.nativeMediaKeySession_ = null;

        /** @private {MSMediaKeys} */
        this.nativeMediaKeys_ = nativeMediaKeys;

        // Promises that are resolved later
        /** @private {shaka.util.PublicPromise} */
        this.generateRequestPromise_ = null;

        /** @private {shaka.util.PublicPromise} */
        this.updatePromise_ = null;

        /** @private {!shaka.util.EventManager} */
        this.eventManager_ = new shaka.util.EventManager();

        /** @type {string} */
        this.sessionId = '';

        /** @type {number} */
        this.expiration = NaN;

        /** @type {!shaka.util.PublicPromise} */
        this.closed = new shaka.util.PublicPromise();

        /** @type {!shaka.polyfill.PatchedMediaKeysMs.MediaKeyStatusMap} */
        this.keyStatuses =
        new shaka.polyfill.PatchedMediaKeysMs.MediaKeyStatusMap();
      }

      /** @override */
      generateRequest(initDataType, initData) {
        shaka.log.debug('PatchedMediaKeysMs.MediaKeySession.generateRequest');

        this.generateRequestPromise_ = new shaka.util.PublicPromise();

        try {
          // This EME spec version requires a MIME content type as the 1st param
          // to createSession, but doesn't seem to matter what the value is.

          // NOTE: IE11 takes either Uint8Array or ArrayBuffer, but Edge 12 only
          // accepts Uint8Array.
          this.nativeMediaKeySession_ = this.nativeMediaKeys_.createSession(
              'video/mp4', shaka.util.BufferUtils.toUint8(initData), null);

          // Attach session event handlers here.
          this.eventManager_.listen(this.nativeMediaKeySession_, 'mskeymessage',
          /** @type {shaka.util.EventManager.ListenerType} */
              ((event) => this.onMsKeyMessage_(event)));
          this.eventManager_.listen(this.nativeMediaKeySession_, 'mskeyadded',
          /** @type {shaka.util.EventManager.ListenerType} */
              ((event) => this.onMsKeyAdded_(event)));
          this.eventManager_.listen(this.nativeMediaKeySession_, 'mskeyerror',
          /** @type {shaka.util.EventManager.ListenerType} */
              ((event) => this.onMsKeyError_(event)));

          this.updateKeyStatus_('status-pending');
        } catch (exception) {
          this.generateRequestPromise_.reject(exception);
        }

        return this.generateRequestPromise_;
      }

      /** @override */
      load() {
        shaka.log.debug('PatchedMediaKeysMs.MediaKeySession.load');

        return Promise.reject(
            new Error('MediaKeySession.load not yet supported'));
      }

      /** @override */
      update(response) {
        shaka.log.debug('PatchedMediaKeysMs.MediaKeySession.update');

        this.updatePromise_ = new shaka.util.PublicPromise();

        try {
          // Pass through to the native session.
          // NOTE: IE11 takes either Uint8Array or ArrayBuffer, but Edge 12 only
          // accepts Uint8Array.
          this.nativeMediaKeySession_.update(
              shaka.util.BufferUtils.toUint8(response));
        } catch (exception) {
          this.updatePromise_.reject(exception);
        }

        return this.updatePromise_;
      }

      /** @override */
      close() {
        shaka.log.debug('PatchedMediaKeysMs.MediaKeySession.close');

        try {
          // Pass through to the native session.
          // NOTE: IE seems to have a spec discrepancy here - v2010218 should
          // have MediaKeySession.release, but actually uses "close". The next
          // version of the spec is the initial Promise based one, so it's not
          // the target spec either.
          this.nativeMediaKeySession_.close();

          this.closed.resolve();
          this.eventManager_.removeAll();
        } catch (exception) {
          this.closed.reject(exception);
        }

        return this.closed;
      }

      /** @override */
      remove() {
        shaka.log.debug('PatchedMediaKeysMs.MediaKeySession.remove');

        return Promise.reject(new Error('MediaKeySession.remove is only ' +
        'applicable for persistent licenses, which are not supported on ' +
        'this platform'));
      }

      /**
       * Handler for the native keymessage event on MSMediaKeySession.
       *
       * @param {!MediaKeyEvent} event
       * @private
       */
      onMsKeyMessage_(event) {
        shaka.log.debug('PatchedMediaKeysMs.onMsKeyMessage_', event);

        // We can now resolve this.generateRequestPromise, which should be
        // non-null.
        goog.asserts.assert(this.generateRequestPromise_,
            'generateRequestPromise_ not set in onMsKeyMessage_');
        if (this.generateRequestPromise_) {
          this.generateRequestPromise_.resolve();
          this.generateRequestPromise_ = null;
        }

        const isNew = this.keyStatuses.getStatus() == undefined;

        const event2 = new shaka.util.FakeEvent('message', {
          messageType: isNew ? 'license-request' : 'license-renewal',
          message: shaka.util.BufferUtils.toArrayBuffer(event.message),
        });

        this.dispatchEvent(event2);
      }

      /**
       * Handler for the native keyadded event on MSMediaKeySession.
       *
       * @param {!MediaKeyEvent} event
       * @private
       */
      onMsKeyAdded_(event) {
        shaka.log.debug('PatchedMediaKeysMs.onMsKeyAdded_', event);

        // PlayReady's concept of persistent licenses makes emulation difficult
        // here. A license policy can say that the license persists, which
        // causes the CDM to store it for use in a later session.  The result
        // is that in IE11, the CDM fires 'mskeyadded' without ever firing
        // 'mskeymessage'.
        if (this.generateRequestPromise_) {
          shaka.log.debug('Simulating completion for a PR persistent license.');
          goog.asserts.assert(!this.updatePromise_, 'updatePromise_ and ' +
              'generateRequestPromise_ set in onMsKeyAdded_');
          this.updateKeyStatus_('usable');
          this.generateRequestPromise_.resolve();
          this.generateRequestPromise_ = null;
          return;
        }

        // We can now resolve this.updatePromise, which should be non-null.
        goog.asserts.assert(this.updatePromise_,
            'updatePromise_ not set in onMsKeyAdded_');
        if (this.updatePromise_) {
          this.updateKeyStatus_('usable');
          this.updatePromise_.resolve();
          this.updatePromise_ = null;
        }
      }

      /**
       * Handler for the native keyerror event on MSMediaKeySession.
       *
       * @param {!MediaKeyEvent} event
       * @private
       */
      onMsKeyError_(event) {
        shaka.log.debug('PatchedMediaKeysMs.onMsKeyError_', event);

        const error = new Error('EME PatchedMediaKeysMs key error');
        error.errorCode = this.nativeMediaKeySession_.error;

        if (this.generateRequestPromise_ != null) {
          this.generateRequestPromise_.reject(error);
          this.generateRequestPromise_ = null;
        } else if (this.updatePromise_ != null) {
          this.updatePromise_.reject(error);
          this.updatePromise_ = null;
        } else {
          // Unexpected error - map native codes to standardised key statuses.
          // Possible values of this.nativeMediaKeySession_.error.code:
          // MS_MEDIA_KEYERR_UNKNOWN        = 1
          // MS_MEDIA_KEYERR_CLIENT         = 2
          // MS_MEDIA_KEYERR_SERVICE        = 3
          // MS_MEDIA_KEYERR_OUTPUT         = 4
          // MS_MEDIA_KEYERR_HARDWARECHANGE = 5
          // MS_MEDIA_KEYERR_DOMAIN         = 6

          switch (this.nativeMediaKeySession_.error.code) {
            case MSMediaKeyError.MS_MEDIA_KEYERR_OUTPUT:
            case MSMediaKeyError.MS_MEDIA_KEYERR_HARDWARECHANGE:
              this.updateKeyStatus_('output-not-allowed');
              break;
            default:
              this.updateKeyStatus_('internal-error');
              break;
          }
        }
      }

      /**
       * Updates key status and dispatch a 'keystatuseschange' event.
       *
       * @param {string} status
       * @private
       */
      updateKeyStatus_(status) {
        this.keyStatuses.setStatus(status);
        const event = new shaka.util.FakeEvent('keystatuseschange');
        this.dispatchEvent(event);
      }
    };


/**
 * @summary An implementation of MediaKeyStatusMap.
 * This fakes a map with a single key ID.
 *
 * @todo Consolidate the MediaKeyStatusMap types in these polyfills.
 * @implements {MediaKeyStatusMap}
 */
shaka.polyfill.PatchedMediaKeysMs.MediaKeyStatusMap = class {
  constructor() {
    /**
     * @type {number}
     */
    this.size = 0;

    /**
     * @private {string|undefined}
     */
    this.status_ = undefined;
  }

  /**
   * An internal method used by the session to set key status.
   * @param {string|undefined} status
   */
  setStatus(status) {
    this.size = status == undefined ? 0 : 1;
    this.status_ = status;
  }

  /**
   * An internal method used by the session to get key status.
   * @return {string|undefined}
   */
  getStatus() {
    return this.status_;
  }

  /** @override */
  forEach(fn) {
    if (this.status_) {
      fn(this.status_, shaka.media.DrmEngine.DUMMY_KEY_ID.value());
    }
  }

  /** @override */
  get(keyId) {
    if (this.has(keyId)) {
      return this.status_;
    }
    return undefined;
  }

  /** @override */
  has(keyId) {
    const fakeKeyId = shaka.media.DrmEngine.DUMMY_KEY_ID.value();
    if (this.status_ && shaka.util.BufferUtils.equal(keyId, fakeKeyId)) {
      return true;
    }
    return false;
  }

  /**
   * @suppress {missingReturn}
   * @override
   */
  entries() {
    goog.asserts.assert(false, 'Not used!  Provided only for the compiler.');
  }

  /**
   * @suppress {missingReturn}
   * @override
   */
  keys() {
    goog.asserts.assert(false, 'Not used!  Provided only for the compiler.');
  }

  /**
   * @suppress {missingReturn}
   * @override
   */
  values() {
    goog.asserts.assert(false, 'Not used!  Provided only for the compiler.');
  }
};


shaka.polyfill.register(shaka.polyfill.PatchedMediaKeysMs.install);
